The present invention relates to the use of a polyethylene glycol compound which is a polyethylene glycol having a molecular weight of 3,000-15,000 and/or a special ethylene oxide adduct which in an amount of at least 75% by weight consists of ethyleneoxy units in an animal feed, which contains pulverulent or granular nutritious substances. The addition of the polyethylene glycol compound to the feed has been found to improve the nutritive value of the feed, for instance for poultry, pigs and calves.
It is generally known to disperse fat in water with the aid of surface-active agents, such as castor oil ethoxylate and lecithin, in order to obtain a formula primarily destined for calves. It is also known to incorporate surface-active compounds into pulverulent or granular feed based on cereals and fat, by admixing them to a fatty phase which is in the liquid state, optionally after heating, so as to increase the availability of the nutritive value of the fat.
From, for instance, a doctor""s thesis by Christoph Gunther: Einfluss von Emulgatoren auf die Verwendung tierischen Fettes von Masthxc3xcnerkxc3xcken at the Hohe Landwirt-schaftlische Fakultxc3xa4t der Reinischen Friedrich-Wilheims-Universitxc3xa4t zu Bonn, Feb. 16, 1988, it is thus known to produce a chicken-feed by mixing various nutritious substances, such as cereals and melted fat. Emulsifiers, such as soybean lecithin, sugar ester, polyoxyethylene glyceryl monostearate and mixtures of castor oil ethoxylate and soybean lecithin are added to the fat in order to improve its digestibility.
From an article entitled Growth Promotion in Broilers by Copolymer CRL 87-61xe2x80x2, by J. P. Texton et al in J.APPL. Poultry Res. (1992)1, pp 373-81, it is also known to add nonionic surface-active block copolymers of ethylene oxide and propylene oxide, for example in contents of 10 ppm, to chicken-feed in an attempt at promoting the growth of chickens. According to the article, the surface-active co-polymer was mixed first with a premix of maize meal and then with the remaining ingredients of the feed. When the chickens were fed with this feed, their growth increased somewhat and their mortality was reduced after 42 days, but not after 21 days. The results obtained have, however, been questioned by William A Duclley-Cash in an article published in Feedstuffs, Mar. 1, 1993, p. 13.
Furthermore, EP-A-217 631 discloses the addition of a water-soluble adjuvent such as a polyethylene glycol having a molecular weight of from about 4000 to about 8000 and a melting point of from 50xc2x0 C. to 85xc2x0 C. to a feed premix containing nicarbazin in order to reduce the drawbacks caused by the electrostatic properties of nicarbazin.
The object of the present invention is to improve the availability of the nutritious substances in conventional animal feed, especially for poultry, pigs and calves, in order to increase the growth per weight unit of feed and/or the daily growth while reducing the mortality.
It has now surprisingly been found that this object can be achieved by using a polyethylene glycol compound selected from a group consisting of
a) a polyethylene glycol having a molecular weight of 3,000-15,000,
b) an ethoxylate of a carboxylic acid having 8-24 carbon atoms,
c) an ethoxylate of a mono-, di- or triglyceride containing at least one acyl group having 8-24 carbon atoms,
d) an ethoxylate of a mono-, di- or triester of sorbitan with a carboxylic ester having 8-24 carbon atoms, and
e) an ethoxylate of an alcohol having 8-24 carbon atoms,
wherein the ethoxylates b), c), d) and e) have a molecular weight of 15,000 at most and in an amount of more than 75% by weight consist of ethyleneoxy units in order to improve the nutrient value of an animal feed containing pulverulent or granular nutritious substances. The reason why the presence of the polyethylene glycol compound results in a higher nutritive value is not known, but it would seem that the strongly hydrophilic polyethylene glycol compound increases the availability of the pulverulent or granular nutritious substances and/or facilitates the assimilation thereof. The amount of the polyethylene glycol compound usually is 10-1500 ppm, preferably 20-500 ppm.
The polyethylene glycol compound, which is hydrophilic, has a HLB value of at least 15, preferably at least 17. It preferably has a molecular weight of 5,000-12,000 and preferably contains more than 85% by weight of ethyleneoxy units. Suitable compounds are e.g. polyethylene glycols, such as polyethylene glycol having a molecular weight of about 6,000. The ethoxylates according to b)-e) are suitably based on naturally occurring compounds which are biologically compatible. Examples are ethoxylates of fatty acids having 8-24 carbon atoms, preferably 10-22 carbon atoms, which means mono- or diesters with oleic acid, soybean fatty acids, tallow fatty acids, rape-seed fatty acids, linseed oil fatty acids and coconut fatty acids; ethoxylates of mono-, di- or triglycerides, such as ethoxylates of glycerides based on tallow fatty acids, oleic acid, soybean fatty acids, rape-seed fatty acids and coconut fatty acids; and ethoxylates of mono-, di- or triesters between sorbitan and fatty acids, such as tallow fatty acids, oleic acid, soybean fatty acids, castor-oil fatty acids, rape-seed fatty acids and coconut fatty acids. Further examples of polyethylene glycol compounds are alcohol ethoxylates, in which the alcohol has been obtained by hydration of natural fatty acids having 8-24, preferably 10-22 carbon atoms. A most convenient ethoxylate is castor-oil ethoxylate having a molecular weight of about 5,000 to about 11,000, which promotes both the growth and the health of the animals even at low dosages.
The present invention also encompasses an animal feed, which preferably is dry and contains a polyethylene glycol compound selected from the groups b)-e).
When producing the animal feed where a polyethylene glycol compound of the present invention are used, the polyethylene compound is suitably produced by mixing the polyethylene glycol compound, which optionally is dissolved or suspended in water and/or applied to a carrier, with the pulverulent or granular nutritious substances or other solid components of the animal feed or a mixture of two or more of these components. If the feed contains a liquid hydrophobic component, such as a lipid or a carboxylic acid, this component is suitably added before or after mixing the polyethylene glycol compound with the pulverulent or granular nutritious substances or other solid components. It is also possible to add the polyethylene glycol compound directly to the liquid hydrophobic component, since the strongly hydrophilic polyethylene glycol compound is not soluble or easily emulsifiable in the hydrophobic component.
When preparing the animal feed, a premix is suitably prepared, consisting of e.g. vitamins, flavourings, minerals, enzymes, antibiotics and probiotics. It is possible to add to the premix dry components consisting of cereals, such as ground or crushed wheat, oats, barley, maize and rice; vegetable protein feed based on e.g. rape, soy and sunflower; animal protein feed, such as protein E, blood meal, bone meal and fish meal; molasses; and milk products, such as various milk powders and whey powders. To this mixture or to the premix, addition is suitably made of the polyethylene glycol compound, optionally dissolved or emulsified in water and/or applied to a carrier, which consists of e.g. ground cereals, starch or inorganic minerals, such as silicates. After mixing all the dry additives, the hydrophobic component, which is liquid, optionally after heating, can be added. It may consist of lipids, such as fat, and/or of carboxylic acids, such as a fatty acid. The lipids usually consist of slaughter fat and vegetable fat, optionally liquefied by heating. After thorough mixing, a mealy or particulate composition is obtained, depending on the degree of grinding of the ingredients. If required, the hydrophobic component, which is liquid, optionally after heating, can be added to the solid pulverulent or particulate components, or a part thereof, in order to produce a solid pulverulent mixture before adding the polyethylene glycol compound.
Within the scope of the invention, it is also possible to produce a suspension of the animal feed. This is especially convenient if the feed is prepared for immediate consumption.
Animal feed according to the invention usually contains, in addition to the polyethylene glycol compound, 0-80, preferably 10-70% by weight of cereals; 0-30, preferably 0-15 and most preferred 1-8% by weight of feed fat; 0-85, preferably 10-50% by weight of protein-containing nutritious substances of a type other than cereals; and 0-12, preferably 1-10% by weight of vitamins, minerals, enzymes, flavourings, antibiotics, probiotics, and optionally other additives usually included in animal feed. To prevent separation during storage, one should suitably add water to the animal feed and subject it to a conventional pelletising, expanding or extruding process. If, after such treatment, the animal feed contains an excess of water, this can be removed by drying. If considered suitable, the resulting granular animal feed can also be crushed to a smaller particle size.